A recent thread on the ‚Digital Photography Review’ Nikon Forum set me wondering.
It concerned a seeming ‘Street Actor’ who, on seeing his picture was being taken, demanded a pound payment from the surprised ‘snapper’. The Snapper didn’t pay up but he did pose the question ‘Is it customary to pay in such a situation? Was I wrong?’
As he puts it:

"It would be different if he had been doing something such as a street performer, or had at least stood for the pic... but I just didnt feel like I owed him anything.. his outfit was screaming "take my picture", and from such a distance I didnt feel like I had invaded his privacy... He was apparently some sort of street performer as I saw him later walking around in the same area greeting people (big ben, thames river area)"

It appears that, had the man been openly ‘performing’ something then dropping money in a hat/tin cup would be in order – but instead he was seemingly ‘off duty’. Someone else suggested that people who just dress up and ‘stand still’ (human statues) shouldn’t even qualify if they have a tin cup since standing still isn’t actually doing anything so they’re strictly not ‘performing’. Further posters claimed that anyone in a public place is public property so to speak and so must accept being photographed.

Even if this is true, and I’m not sure it is, there is a can of worms further down the argument. If you are expecting to receive some financial reward for the persons image then payment seems appropriate – and indeed professionally speaking a model release form should be used. Street photographers though usually don’t know what will turn out to be a valuable shot and in truth any shot may have a value you don’t know about – that man and woman holding hands may be married, but not to each other! That man hurrying down the High Street may have reason to tell police officers he was not even in the City you just snapped him in.

Lets take a ‘best case scenario’:
You snap two old ladies laughing at a bus stop. No money in a picture like that seemingly. unlikely they need alibis and famous they are not. Well how about all those postcards you see with old sepia coloured images from bygone days and ‘funny’ texts?
These unwitting 'models' certainly never thought they would be a part of big business – and the postcard people have a huge and cheap source of ‘models’ who won’t need paying – ever. Had that old lady gurning inadvertently into a camera in 1930 and out of a postcard in 2006 in her best dress and on her brand new bicycle asked to sign model release forms in 1930 she would have been laughed at.

You never know what will sell.

Perhaps us photographers just need to take quick pictures in the streets and ‘sit on’ them for twenty years just to be on the safe side… Or pay a pound now?!